1. Field of the Invention
This invention relates to the field of anti-skid devices for motorized vehicles. Cam action on a piston in the hydraulic system causes the pressure in that system to alternately increase and decrease thereby exerting a pumping action on the brake cylinder.
2. Description of the Prior Art
The problem of skidding in motor vehicles is not new and systems to cope with this problem are known in the prior art. Typically, the prior art systems include either a wheel-driven pump or a flyball approach. For instance, the Roberts U.S. Pat. No. 2,919,162 illustrates a prior art system in which a wheel-driven pump is employed. Perrino U.S. Pat. No. 3,325,226 and Stager et al. U.S. Pat. No. 3,046,060 are typical of prior art systems employing flyball lag. Skoyles U.S. Pats. No. 3,524,684 and 3,574,416 show anti-lock brake systems using a cam and piston technique. These latter systems do not produce any pumping action and they further depend on a pump operating independently of the wheels.
There are several drawbacks to the typical prior art systems. Many prior art systems depend upon pumps and other auxiliary equipment for taking brake control from the vehicle operator. Also, due to the inertia of many prior art systems there is a time lag between the reaction of the driver and the application of some anti-skid countermeasure to the wheel. Furthermore, many prior art systems do not include fail-safe features to protect against internal failure of the anti-skid mechanism. It was to overcome the foregoing disadvantages of many prior art systems that the disclosed invention was perfected.